U.S. Pat. No. 6,628,382 discloses a method and apparatus for performing spectrophotometric measurements on a sample that was pulled into a measurement column between two parallel opposing surfaces. A drop of the sample is held between the two opposing surfaces by surface tension. One of the surfaces can be controllably moved toward and away from the other. Each surface contains an optical fiber mounted coaxially with the surface and perpendicular to the surface. Each optical fiber goes through its surface and is finished flush with the surface, to provide and transmit exciting energy through the drop for measurement.
U.S. Pat. No. 8,223,338 discloses a method for performing spectrophotometric measurements on a sample pulled into a liquid column by surface tension. The sample is held between two opposing substantially parallel upper and lower surfaces by interfacial tension. The upper surface moves down so as to engage the sample, and subsequently moves upward and away from the lower surface. In this manner, interfacial tension is used to adhere the sample to the lower and upper surfaces, such that surface tension forms a liquid column of a mechanically controlled path length. The path length is controlled by a solenoid mounted below the apparatus. U.S. Pat. No. 8,189,199 discloses a similar method of forming a liquid column using surface tension.
EP Patent No. 1 743 162 B1 discloses a device having integrated beam switching systems with a detachable reflector. The device uses fiber optics for guiding light used in analysis of a liquid medium in a spectrophotometer, a spectrofluorometer or a similar measuring device. The light is guided to a measuring point located on the device, which is a receiving surface for the medium, and back therefrom to a detector. The receiving surface forms a flat measuring point on an upper side of the device and is closed by a cover-type detachable reflector in a position of use. The reflector is in close contact with a sample of the medium and can be removed before application of the sample and for cleaning the measuring point.
EP Patent No. 1 910 807 B1 discloses a device for performing absorption measurements using a detachable reflector. The device has an upper planar portion for applying a medium, a light entry portion in a housing arranged beneath the upper planar portion and a deflector in a light beam behind the light entry portion for deflection of the light upwards to an upper planar portion where a detachably mounted reflector is also located. The deflector is designed such that a direction of an optical axis of a deflected light beam is oriented upwards toward a middle of the device, and an inclined position of the optical axis of the light beam with regard to the device mid-point is arranged to be directed at a position of the reflector through which a longitudinal median between the light entry portion and a light exit from the device extends.